Researchers at the East Texas Medical Center and the University of North Carolina have discovered that vitamin D helps to regulate the sleep-wake cycle. They've found a definite link between vitamin D deficiency and the current global epidemic of sleep disorders.

Rapid eye movement sleep (REM) is one of the deepest levels of sleep. It is the level in which dreaming occurs, and its related to good memory and learning. A disruption of REM sleep or an absence of it, is one form of insomnia. Other sleep disorders include sleep apnea - which involves interrupted or obstructed breathing or snoring during the night; insomnia from hormone fluctuations such as with menstruation or menopause; restless leg syndrome; and periodic limb movement disorder, a condition where the person moves their limbs involuntarily during sleep.

The results of the clinical trial of vitamin D supplementation were published in a recent issue of the journal "Medical Hypothesis". The researchers followed 1500 patients over a 2 year period. A consistent level of vitamin D3 was maintained in their blood over many months. This produced normal sleep in most of the participants, regardless of their type of sleep disorder, which suggests that many types of insomnia may share the same cause. During the research, the authors discovered the presence of high concentrations of vitamin D "receiving sites" or "receptors" in those areas of the brain that are related to the onset and maintenance of sleep.

The authors of the vitamin D study note that sleeping disorders have played a role in the development of medical conditions such as hypertension, heart disease, stroke, diabetes, depression, and chronic pain -- all of which have become widespread similarly to insomnia. The authors suggest further research be done on the management of vitamin D levels in a variety of medical conditions related to sleep.